Pumping arrangement

Abstract

A pumping arrangement, for example for liquid chromatography, includes a first liquid reservoir at a first height level, connected via a first hydraulic path to a pumping device; a second liquid reservoir at a second height level, connected via a second hydraulic path to the pumping device; and filtration devices arranged in the first and in the second hydraulic path. Each filtration device includes an outer member forming a first chamber, and an inner member arranged within the outer member and forming a second chamber. The inner member is porous and acts as a filter for liquid flowing from the first chamber to the second chamber. The arrangement ensures efficient filtering and prevents undesired backflow of liquid.

What is claimed is:  
     
       1. A pumping assembly comprising: 
       a first liquid reservoir at a first height level, connected via a first hydraulic path to a pumping means;  
       a second liquid reservoir at a second height level, connected via a second hydraulic path to the pumping means; and  
       first and second filtration devices arranged in the first and second hydraulic path, respectively, wherein each filtration device comprises an outer member forming a first chamber, and an inner member arranged within the outer member and forming a second chamber, with the inner member being porous for allowing liquid flow from the first chamber to the second chamber.  
     
     
       2. The pumping assembly as in  claim 1 , wherein the pumping means comprises a first pump module connected to the first hydraulic path and a second pump module connected to the second hydraulic path, and wherein the filtration devices are arranged at the same height level. 
     
     
       3. Pumping assembly as in  claim 2 , wherein the filtration devices are identical. 
     
     
       4. Pumping assembly as in  claim 1  wherein the first chamber is designed for accommodating a multi phase system comprising a liquid phase, and a gas phase comprising vapor of the liquid from the first or second liquid reservoirs. 
     
     
       5. Pumping arrangement as in  claim 4 , wherein the gas phase has a volume of at least 50% of the liquid phase. 
     
     
       6. Pumping assembly as in  claim 1 , wherein the outer member of the filtration device is formed of borosilicate glass. 
     
     
       7. Pumping assembly as in  claim 1 , wherein the inner member of the filtration device is formed of sintered borosilicate glass. 
     
     
       8. Pumping assembly as in  claim 1 , wherein the filtration device comprises an insert made of PTFE-which is arranged at the end of the outer member and which contributes to a sealing connection of the filtration device with a connected tube. 
     
     
       9. Pumping assembly as in  claim 1 , wherein the volume in the hydraulic path between the liquid reservoir and the filtration device, and the gas volume which can be accommodated in the filtration device are matched such as to allow optimum liquid priming before the pumping operation of the pumping assembly starts.